diff --git a/streampipes-wrapper-python/requirements.txt b/streampipes-wrapper-python/requirements.txt
index 4ebe9a9a69..7c51160b43 100644
--- a/streampipes-wrapper-python/requirements.txt
+++ b/streampipes-wrapper-python/requirements.txt
@@ -1,4 +1,4 @@
-bjoern==3.1.0
+waitress==-1.4.4
 certifi==2020.6.20
 chardet==3.0.4
 click==7.1.2
diff --git a/streampipes-wrapper-python/setup.py b/streampipes-wrapper-python/setup.py
index a4e074cfc4..89b69eaa9b 100644
--- a/streampipes-wrapper-python/setup.py
+++ b/streampipes-wrapper-python/setup.py
@@ -43,7 +43,7 @@
         'Flask==1.1.2',
         'flask-classful==0.14.2',
         'Flask-Negotiate==0.1.0',
-        'bjoern==3.1.0',
+        'waitress==1.4.4',
         'python-consul==1.1.0'
     ],
     tests_require=[],
diff --git a/streampipes-wrapper-python/streampipes/api/resources/base.py b/streampipes-wrapper-python/streampipes/api/resources/base.py
index 76f92f4ce6..ebee17ec0a 100644
--- a/streampipes-wrapper-python/streampipes/api/resources/base.py
+++ b/streampipes-wrapper-python/streampipes/api/resources/base.py
@@ -16,7 +16,7 @@
 #
 import abc
 import os
-from flask import jsonify, make_response
+from flask import jsonify, make_response, request
 from flask_classful import FlaskView, route
 from flask_negotiate import consumes
 
@@ -85,6 +85,7 @@ class InvocableElement(Element):
     def invoke_runtime(self, element_id: str):
         # TODO: parse invocation graph
         # payload = request.json
+        print(request.json)
         resp = {'element_id': element_id, 'status': 'sucess'}
         return make_response(jsonify(resp), 200)
 
diff --git a/streampipes-wrapper-python/streampipes/api/rest.py b/streampipes-wrapper-python/streampipes/api/rest.py
index 61d828d980..9f47a4d807 100644
--- a/streampipes-wrapper-python/streampipes/api/rest.py
+++ b/streampipes-wrapper-python/streampipes/api/rest.py
@@ -17,7 +17,7 @@
 """ API endpoints """
 import threading
 
-import bjoern
+from waitress import serve
 from flask import Flask
 
 from streampipes.api.resources.dummy import DummyInterimsResource
@@ -44,6 +44,6 @@ def __init__(self):
             DummyInterimsResource.register(self.app, route_base='/')
 
     def run(self, port: int):
-        print('serving API via bjoern WSGI server ... http://{}:{}'.format('0.0.0.0', port))
-        threading.Thread(target=bjoern.run, args=(self.app,), kwargs={'host': '0.0.0.0', 'port': int(port)}).start()
+        print('serving API via waitress WSGI server ... http://{}:{}'.format('0.0.0.0', port))
+        threading.Thread(target=serve, args=(self.app,), kwargs={'host': '0.0.0.0', 'port': int(port), '_quiet': True}).start()
 
diff --git a/streampipes-wrapper-python/streampipes/core.py b/streampipes-wrapper-python/streampipes/core.py
index cf21c91690..543f5d7901 100644
--- a/streampipes-wrapper-python/streampipes/core.py
+++ b/streampipes-wrapper-python/streampipes/core.py
@@ -24,7 +24,7 @@
 
 
 class EventProcessor(object):
-    __metaclass__ = abc.ABC0
+    __metaclass__ = abc.ABC
 
     _DEFAULT_KAFKA_CONSUMER_CONFIG = {
         'bootstrap.servers': 'kafka:9092',
diff --git a/streampipes-wrapper-python/streampipes/declarer.py b/streampipes-wrapper-python/streampipes/declarer.py
index 35c0b17f05..40ab81072c 100644
--- a/streampipes-wrapper-python/streampipes/declarer.py
+++ b/streampipes-wrapper-python/streampipes/declarer.py
@@ -51,10 +51,10 @@ def get_processor(cls, key):
     def get(cls):
         return cls._processors
 
-    # def get_declarers(self):
-    #     return self.sepa_declarers
-    #
-    # def get_base_uri(self):
-    #     return 'http://' + self.host + ':' + self.port + self.route
+    def get_declarers(self):
+        return self.sepa_declarers
+
+    def get_base_uri(self):
+        return 'http://' + self.host + ':' + self.port + self.route